Vacuum cup systems have been in use for lifting glass and metal plates, or other industrial parts having nonporous surface. In the event that the source of vacuum pressure is lost, the grip of the vacuum cups on the workpieces being lifted and moved can be lost resulting in potential damage to surrounding equipment, or injury to operating personnel. Therefore, it is desirable in the present invention to provide a safety device that can maintain the vacuum pressure within a vacuum cup after the failure of the source of vacuum until positively released.